Plunge Control
Mechanical limitation of vertical tool travel governs the final floor thickness of routed printed circuit boards during high speed sub panel separation. Tool breakage destroys thin dielectric layers when spindle movement overshoots the programmed contour. Operators deploy a micro milling depth stop to restrict z axis descent before mechanical force damages internal copper planes.
Rotary spindles mount directly against the physical collar, stopping downward feed the instant the reference face contacts the sacrificial backing material. Subcontractors inspect finished panels using optical coordinate measuring machines to verify cavity floors meet drawing tolerances. Excessive downward force bends tiny carbide bits, leaving micro cracks across the laminate.
Vertical Boundary
Spindle positioning relies on pneumatic pressure balancing the tool carriage against a precision ground foot. Thermal expansion shifts spindle heights during lengthy production runs, requiring constant calibration of the contact sensor. Machinists check zero points before routing rigid flex layers because material swelling alters the resting plane.
Pneumatic circuits maintain constant downward load while the mechanical collar halts the stroke at the exact threshold. Optical inspection flags any residual burrs left by worn bits dragging across copper traces.
Tolerance Verification
Laser displacement sensors measure the resulting pocket depth during offline auditing of finished circuit boards. Production lines reject assemblies where vertical positioning drifts beyond the micron limit specified in fabrication drawings. Mechanical wear degrades the contact face over thousands of routing cycles, causing gradual depth creep across panel batches.
Tooling engineers replace worn collars before dimensional variation pushes the finished routing depth outside allowable engineering limits.
